Sickle guard



Oct. 13, 1953 E. L. MILLS ET AL SICKLE GUARD 5 Sheets-Sheet 1 Filed May 20. 1948 I N V EN TORS @QWdIA/ZZ? Jams diam/Jae Oct. 13, 1953 E. L. MILLS ETAL SICKLE GUARD 5 Sheets-Sheet 2 Filed May 20, 1948 Mdldf JNVENTORS E. L. MILLS ET AL Oct 13, 1953 SICKLE GUARD 5 Sheets-Sheet 5 Filed May 20, 1948 Oct. 13, 1953 E. L. MILLS ET AL 1 SICKLE GUARD 5 Sheets-Sheet 4 Filed May 20, 1948 Oct. 13, 1953 E. MILLS ET AL 2,654,987

SICKLE GUARD Filed May 20, 1948 5 Sheets-Sheet 5 IN VEN TOR-5 m .wmdi

Java; (230 Patented Oct. 13, 1953 SICKLE GUARD Edward L. Mills and Dennis A. Donahue, Bu-

chanan, Mich., assignors to Buchanan Steel Products Corporation, Buchanan, Mich., a corporation of Michigan Application May 20, 1948, Serial No. 28,196

2 Claims.

This invention relates to sickle or cutter guards of the type used on harvesting machinery such as mowers and the like.

Cutter guards of the type defined are conventionally formed of cast iron, and are provided with a so-called ledger plate over which the associated cutting knife slides, the grass or other material to be out being caught between the knife blade and the edge of the ledger plate and thus severed. Such constructions have certain disadvantages among which is the fact that the cast metal of which the cutter guard is formed is brittle so that it is readily broken by rocks or other foreign objects with which it may be inadvertently engaged or struck during operation of the associated harvesting machine. Further, the brittle characteristic of the metal does not permit of its being bent back into shape, for further service, in the event of bending or jamming by engagement with such foreign objects. Still further, the requirement for a ledger plate, as a separate element, to provide a hard surface against which the cutting knife may engage, increases costs and gives rise to various manufacturing difficulties incident to the securing of the ledger plate in position upon the body of the cutter guard.

A forged cutter guard, forged to shape from suitably constituted steel, and case hardened, eliminates the necessity for a separate ledger plate, in that a case hardened surface may be formed upon the cutter guard body to effect the functions of a ledger plate. Furthermore, a properly forged steel guard, while externally case hardened, may be left with a relatively tough and duetile core or interior, so that the guard member is relatively non-brittle, and bendable within limits. The danger of breaking by inadvertent engagement with foreign objects such as rocks, as above mentioned, is thereby minimized; and in the event the guard body should become inadvertently bent it frequently may be 'restraightened for further service avoiding replacement costs.

While various advantages thus result from the provision of a cutter guard of forged steel, difliculties also arise incident thereto, particularly in providing satisfactory means and methods of fabrication and assembly. Certain of these difiiculties arise in and are incident to the provision of cutter guards of the multiple finger type as is set forth in our copending application, Serial No. 693,516, filed August 28, 1946, now Patent No. 2,619,787, wherein a sickle guard of the multiple type, and methods for effecting the manufacturing thereof, are set forth. Other difficulties and problems arise in connection with the production of a forged cutter guard of the unit or single body type, which comprises the subject matter of the present case.

It is an object of the present invention to provide a cutter guard, specifically of the single body type, of improved construction and improved operating characteristics. a

A further object of the present invention is to provide improved means and methods for effecting the fabrication of sickle or cutter guards of the type set forth.

More specifically stated, one of the objects of the present invention is to provide improved fabricating methods, for guards of the type de fined, which may be more rapidly and economically carried out, and which produce a more accurately formed and fabricated structure.

Another object of the invention is to provide in a guard structure of the type stated, an improved cutting ledge, guard lip, and associated parts.

Still another object of the invention is to provide a cutter guard structure, of the type defined, having improved anchorage means for connection of the guard body to the associated harvester machine frame parts.

Various other objects, advantages and features of the invention will be apparent from the following specification, when taken in connection with the accompanying drawings, wherein certain preferred embodiments are set forth for purposes of illustration.

In the drawings wherein like reference numerals refer to like parts throughout:

Fig, 1 is a perspective view of a sickle or cutter guard constructed in accordance with and embodying the principles of the invention, in accordance with one preferred and selected embodiment thereof;

Fig. 2 is a longitudinal sectional view of the structure of Fig. 1 taken as indicated bythe line 2--2 thereof; 7

Fig. 3 is a top view of the structure;

Fig. 4 is a bottom view thereof;

Figs. 5 to 10 inclusive are transverse sectional views taken as indicated by the lines 5-5 to Ill-i II, respectively, of Fig. 3;

Fig. 11 is an assembly view showing a plurality of the cutter guards assembled in operative posi- 7 tion in a harvesting machine, in cooperation with cutting knives and associated parts;

Fig. 12 is an enlarged sectional view through the structure of Fig. 11, taken as indicated by the line l2-l2 thereof;

Fig. 13 is a sectional view of the structure of Fig. 11 on the line l3-|3;

Fig. 14 is a partial view, similar to Fig. 13, but showing the cutter blade in a different shifted position;

Fig. 15 is an exploded perspective view of the forging die blocks used in fabricating the cutter guard of Fig, 1, in multiple units;

Fig. 16 is an enlarged sectional view through the die cavities, and taken as indicated by the section lines I6l6 of Fig. 15;

Fig. 17 is a perspective view of the forged bl'anlr; as fabricated by the die structures of. Figs. 15 and 16;

Fig. 18 is an exploded perspective view of a set of blanking and trimming die blocks used in the further fabrication of the cutter guard units;

Fig. 19 is a perspective view of the flash sheet of Fig. 17, after the guard bodies have been severed therefrom;

Fig. 20 is an enlarged longitudinal sectional view of one of the guard bodies, as fabricated by the blanking andv trimming dies of Fig. 18;

Fig. 21 is a view similar to Fig. 20, illustrating the manner in which the guard body is sawed: to form the knife overlying guard lip thereon;

Fig. 22 is an illustrative sectional view through the structure of Fig. 21, taken. as indicated by the line 22--22 thereof;

Fig. 23 is a view similar to Fig. 21, but illustrating a modified embodiment;

Fig. 24 is an illustrative sectional view through the structure of Fig. 23, taken as indicatedby the line 24---- 24 thereof;

Fig. 25 is a partial plan view of the structures of Figs. 2324; and

. Figs. 26, 27 and 28 are'plan, side,,and transverse sectional views, respectively of a still further modified form of structure, Fig. 28 being taken on the line 28*28 of Fig. 2'7.

Referring more specifically to the drawings, and first to the structural embodiment of Figs. 1-22 in Figs. 1-10 there is illustrated the structure of the finished guard body, which will be first described.

As shown, the guard comprises a main body 10 having a forward nose or guiding portion [2 and a rear anchorage portion I4. As indicated in- Figs. 2 and 3, the nose portion I2 is tapered both laterally and vertically to form a generally pointed forward nose portion for engagement into the grass or other material to be cut.

A Slut I6, Fig. 2, is formed horizontally into the body, extending toward. the nose I2so as to form an overhanging lip as indicated at I8 extending rearwardly over the main body a predetermifieddistance. The recess [6 is arranged to receive the cutting knives, as will presently appear, the lower surface 20 of the recess comprising a ledger surface against which the cutting edges of the knives engage to effect the cutting action.

The rear anchorage portion [4 of the cutter guard more specifically comprises a centrally disposed cup-shapedrecess portion 22 alignedwith a polygonal opening 24 which is square in cross section in the particular embodiment shown. Thereis further provided, along the forward edge of the anchorage portion, a pair of upstanding lugs 26 forming ledge means and which cooperate with the opening 24 in securing the cutter guard in position, as will presently appear. The anchorage portion 14 is connected to the main body I0 by means of a relatively flat web 28 lying subbody II].

The transverse cross sectional shaping of the structure along its length is shown by the successive sectional views, Figs. 5 to 10 inclusive. It will be seen that the body in the vicinity of the slot 16 is provided with a pair of laterally extending wings 30, Figs. 7 and 8, and with a depending web and stiffening flange 32. The Wings 30 provide: a relatively wide. ledger surface 20, in respect to the size of the structure, and the web 32 imparts a maximum vertical strengtheningin reference to over-all weight.

A plurality of cutter guards in assembled position. in respect to a harvesting machine frame structure, and associated cutting knives, are shown in Figs. 11-14. As indicated in Fig. 12, each guard member is arranged to be secured to the harvester machine frame structure 34 by means of a bolt 36 extending through the squared opening 24, previously described, and secured in position by suitable means such as the nut 38. In the particular arrangement shown, bolts 36 not only secure the individual guards [0 in position. but also may be employed to connect a frame apron. 40 to the frame structure 34, as shown- A knife supportbar 42 overlies the Webs 28 of the cutter guards, said knife bar being. suitably supported upon the harvester machine. frame for reciprocating movement in respect to the cutter guards, in the usual manner. The bar 42 carries knives 44 in abutting relation, the knives lying within the guard member slots I6, and each knife being provided with a cutting edge 46 cooperable with and slidable over the ledger sur- 7 face 20 of the associated guard member.

The method of making the cutter guardsin accordance with the present invention, is illus-- trated in Figs. 15-22. A pair of cooperable forg ing dies is provided as indicated at" 48 and 50,

Fig. 15, both dies being provided with two sets.

of impressions, or cavities as indicated, respec tively, at 52 and 54. The impressions 52, in the particular embodiment shown, are for effecting the rough forging operations, and the impressions 54 are for effecting the finished forging.

In operation, a steel billet 56 0f suitable size and constituency for case hardening is laid onto the lower die block 50, as indicated in dotted lines in. Fig. 15, so that uponclosing of the diesin a suitable drop hammer mechanism a pair of op-- positely extending cutter guards will be fabricated from a single billet. After rough forging by the impressions or cavities 52, the billet is transferred to the cooperative finish cavities 54 wherein the finished forging operations are effected. The

tion, and the lugs 26 thereof, are formed as an incident to the, forging operations.

Referring to Fig. 18, a blanking and. trimming die set is shown comprising a lower die block 60 having adie cavity 62, and an upper die block 64 having a die 66; the die cavity 62 and-die 66.

being cooperatively shaped so that upon actuation within a suitable punch press or the like the.

cutter guards may be individually severed from the flash sheet. The flash, with the cutter guards severed therefrom, is illustrated in Fig.

19, the openings from which the cutter guards:

have been severed being indicated. by the reference numerals 68. After blanking, the squared;

opening 24 may be cut through the recessed portion 22, or such openings may be cut through the anchorage portion of the cutter guards prior to severance from the flash sheet 58.

The guard member In, in the condition in which it emerges from the blanking and trimming dies, and with the opening 24 out therethrough, is shown in Fig. 20. It will be seen that a parting line as indicated at Eli extends along the length of the guard body. The rough edges of this parting line are removed by the blanking dies B2-B6 except along the length represented by the numeral 12 in Fig. 20, along which area a portion of the forging flash at the parting line may be permitted to remain for a purpose as will presently appear. To form the knife slot 20 and the associated lip 18, in each cutter guard, as previously described, a rotary saw it, Fig. 21, suitably mounted in a sawing machine, is employed. In the preferred embodiment illustrated in Figs. 1-22, the saw cut is positioned so as to remove the forging flash it, in the vicinity of the out, which results from the forging and blanking operations as described.

More particularly, referring to Fig. 22, the aforementioned flash portions ii are indicated in dotted lines, and it will be seen that the saw cut is so disposed as to effect the removal of the flash, thereby adding to the finish of the product, and facilitating the formation of a proper cutting edge 14 at the point of juncture between each wing 30 and the ledger surface 22. The arrangement is further illustrated in Fig. 1 wherein it will be seen that the parting line it and saw slot 16 are substantially coplanar so that the flash portion 12 has been removed. As will be understood, in effecting the sawing operation to form the slot 16, the work piece is held in a suitable fixture in reference to the rotating saw blade, and the saw blade then moved downwardly as seen in Fig. 21 to effect a suitable penetration into the work, and a removal of the stock to be out.

After the sawing operation, the work piece is case hardened, particularly in the vicinity of the ledger surface 26 and the cutting edges '54, to provide a hardened surface for engagement by and cooperation with the knife blades 44. Preferably the inner core of the guard body is maintained untreated, for toughness and ductilit It will be seen that in accordance with the method set forth, means are provided for effecting the rapid and economical fabrication of single sickle or cutter guards by means of drop forging operations, whereby to produce a forged cutter guard structure which avoids the necessity for a separate ledger plate, and which is also highly resistive to breakage from shock or impact in service. The arrangement by which the cutter guards are drop forged by closed dies, in multiple units in back to back relationship enables the forging operations to be rapidly and accurately effected, each cutter body lending stability and accuracy to the positioning of the other whereby to facilitate the proper forging of both. Both rough and finished forging operations are effected in this same relationship. The blanking and trimming dies 62-66 perform the dual function of removing the cutter guard bodies from the foregoing flash sheet 58, and also serve as means for trimming the guard bodies around the parting line of the flash so as to provide a finished work piece. In accordance with the embodiment previously described, a portion of the parting line flash as indicated at 12, is removed by the sawing operation, which constitutes a simplified means for thus further finishing the work piece and simultaneously producing the knife blade receiving slot structure.

The lugs 26 and squared opening 24, which are produced in the anchorage portion of the cutter guard, as heretofore described, provide a simpli-" fied means for securing single cutter guard members to the harvester machine frame structure, as indicated in Fig. 11, in aligned relationship. It will be seen that a single securing bolt 36, in combination with the lugs 26, provides a firm yet shallow anchorage for the cutter guards which is strongly resistant to forces tending to twist the guards in respect to their mountings.

The relatively wide ledger surface 20, produced by the outwardly projecting wings 30, extends beyond and is wider than the lip l8 so that a ledger surface of desired size is maintained even after repeated sharpenings. The increased width of the ledger surface in respect to that of the lip minimizes the jamming of the grass or other out material, as does the parallel disposition and positioning of the slot It. The wings 30 also provide increased width to the body I!) in the vicinity of the slot 16, the slot being substantially commensurate in length with the wings, whereby the slot does not unduly weaken the body structure for rugged service conditions. The parting line it, which is stepped downwardly so to speak from the main body I!) to the anchorage portion I4, enables the entire structure to be fabricated by forging, in the manner previously described.

In certain instances it may be desirable to leave a portion of the flash 12, so as to provide additional width to the ledger surface, and also to provide a relatively thin cutting edge which may be readily ground for resharpening. Such a structure may be readily produced, in accordance with the present invention, merely by shifting the position of the saw cut. Thus, as illustrated in the modified embodiment of Figs. 23-25, by shifting the saw cut slightly upwardly of the cutter body as indicated at Illa, it will be seen that the portions of the flash 62a remain unsevered, so that the cutting edges l ia are formed in this instance at the outer edge of the flash. The relatively narrow flash structure, at the parting line, can be readily reground for sharpening operations.

In Figs. 26-28 a further modified embodiment is illustrated wherein the cutter body as indicated at [0b has spacing projections oppositely extending at the rear of the ledger surface. These extensions have a combined length equal to or slightly greater than the width of the anchorage portion [4b so that they may be brought into abutting relation when the guards are assembled in operative position on the harvesting machine, thus lending stability to the assembled unit. Also, the ledger surface forming wings, indicated at 301), are in this instance serrated or roughened along their outer surfaces at 32 whereby to provide serrated cutting edges Mb as in certain instances may be desired to facilitate the cutting action of the knives.

It is obvious that various changes may be made in the specific embodiments set forth without departing from the spirit of the invention. The invention is accordingly not to be limited to the specific embodiment shown and described, but only as indicated in the following claims.

Theinvention. is henemr claimed as follows:

1 A cutter; guamdl 01: use. in- 2; and: fanned; of; fiorgedi sheet and including an; elongated body portion: having. a ledger surface and a lip overlying: the: same, amt fmtthen in? cluding a relatively shallow anchorage. portion ofiset. downwardly from said ledger surface: and, havingformed: thereon aszthe resnltofi thae.fo1:g-ting. operation. a bolt, recess and: lugs; spaced; on; opposite: sides.- theneof' and adjacent the peripheral: edgeof saidi anchorage portion; said; guard; body portion; being provided on opposite sides; thereof and. along? said: ledger" surface with; cutting edges; said, guard body portion and said. anchonage portionhaving; respectively 2.: first: parting line region: and an offset parting line region both resuit-ing fromthe; forging operation and joined by'an intermediate pantingflineusaidl first parting line. region. approximating: the: post-- tien. of said: cutting; edges, and; said ofisenparting; lineregiom extending along the; peripheryof said: anchorage portion the bolt' 1380888 311111. up;- standim; lugs; disposed close to. the said; offset; pantingzline region.

8 2'. A emter'guardlazs claimed in claim; I, whomm the ledger surface; irlcluldes wing: portions can: tending laterally beyond: the adjacent sun-4 faces and having beveled edges intetsectmg: the ledger surmcesfbr providing sharp edges cooperalble. witl'na cutter plate;

EDWARD L. MIDLS.

DENNIS A.

References" Cited inthefile of this"padiudnt UNITED PATENTS 

